I believe Mueller was smart enough to challenge Trump's ego, making him want to face him and answer questions. I think Trump now sees Muller's only desperate move now is to get him to agree to questioning and then trip him up - get him with a 'Gottcha' question, which is exactly the case.Try to focus for a second. Trump said he looked forward to testifying under oath. Did you believe him? I'm curious, because all your arguments appear faith-based.
No way Trump's lawyers allow Trump to do the interview now.
Furthermore, I think Mueller knew this and leaked the questions out himself, just like his team has leaked other information out. he leaks the questions out, CNN et al helps him blame Trump to make Trump look 'dirty', and when Trump says 'No' to the questioning Mueller declares, "SEE - He is hiding something.' ... and stupid snowflakes will believe him....
I think that the funniest thing that could happen would be for Trump to show up to an interview and not answer any question. I'd be ok if he invoked his 5th Amendment right to do it, just refusing to answer would crack me up!